Hugershoff reaction of N-1- or N-2-naphthoyl-N'-monosubstituted and N',N'-disubstituted thiourea derivatives, prepared by the reaction of 1-naphthoyl or 2-naphthoyl isothiocyanate with primary or secondary amines, was studied. Depending on substituents the corresponding urea or benzothiazole derivatives were obtained as reaction products. Their structure was determined on the basis of infrared, 1H and 13C NMR and mass spectra.